1. By 2 years old, I bought her the skuut bike. At first she walked along side it. I resisted the urge to sit her on it immediately, realizing that she needed to get comfortable with it. When she dropped it and worked to pick it back up, I realized she was learning some very basic principles of how it balances even then.
2. I made myself a scoot bike. I needed to be able to show her what she could do with it, since she wasn't able to talk yet. Also, I was kinda jealous of her new ride, and it looked like a lot of fun. We would ride together, and play chase, and have the wheels kiss, and whatever else we could think of to have fun. I would also find lines for us to ride on to practice straight riding.
3. Pedaling on a tricycle. Pretty soon we were scooting to our local bike shop. While we were there, she wanted to ride a cool little tricycle they have. That is how she learned to pedal.
4. Power Pedal Technique (No Wimpy Pedals!). It wasn't long after that, that it was time to start on her 'real' bike, the 'blue bike.' I had a handle attachment that comes off the back. I could help keep her upright with it, but I did not use it to do her work for her. I used it as a safety net. She still had to keep her bike balanced properly (make sure the feet can still touch the ground while seated). At this point, she was able to talk and understand basic instructions. So I talked to her at the same time as showing her. She learned to get a pedal up for a good take off push with her foot. Once she was rolling, she was riding, because she already had her balance from the skuut bike. Again, I did not use the handle to do her balancing for her. I would keep my hand hovering around it, just to be there to help alleviate a fall.
5. Braking. The next step was teaching her how to back pedal for the brakes. To help with 'on the spot' braking, I set up a small kid size stop sign, at which she had to stop directly next to, and look for cars. Actually, I had been implementing that since she started with the skuut bike, so she was used to stopping, but not as much with the new way of braking. It didn't take long before she was able to brake on her own, and keep upright while coming to a stop.
Now she is riding on her own, and doing very well. There are plenty of new bike experiences to come, and she still has alot to learn about riding, but it is exciting to see her naturally lean into a turn, ring her bell as she rides all the while smiling and laughing and having fun.
Here is a link to our first scoot bike ride together. Even though she is not wearing her helmet in this brief video, she always has it on when we are outside. She has been wearing a helmet since she was 1 year old and riding with me in the bike trailer. She loves wearing it, and is quick to remind me if I forget mine!